There are a couple really good versions of this available today, they all work pretty much the same way. The one I am using is Dead Ringer by Tim Wisseman which I chose over the Wenger bell for no particularly good reason. I suppose the Wisseman bell was smaller in size, although both can be put together in front of an audience.
We got the spirit bell for a sports video we were doing about a cursed team and the curse would not die. The town tried burying the curse but it somehow stayed alive and was able to ring the bell at will. It went over well and I thought that might be the end of the spirit bell for me. However I showed it to my wife as an antique (she collects Art Deco period pieces and this fit in). I told her the story of how people use to ring the bell from their coffins and she seemed fascinated by it. While taking out the garbage I activated the bell and when I came in she genuinely freaked out by it.
The Spirit Bell is primarily a seance or parlor effect. The bell is small and not very loud so it does not play well on a stage. However I felt it was worth a shot to try and incorporate it into a living room show I was doing. Problem was that since it was a magic show the effect might lose some of its creepiness so I added the tombstone and patter pretty much as done on the video.
Finding a tombstone that would fit on a magic table and not tip over was not easy, what I found worked the best was an item called "Tombstone Trio" which has 3 tombstones that actually have fold out legs in the back so the will sit properly on a table (They are designed to work with fog machines). The addition of the gravestone compensated the small size of the bell and made a good backdrop for the bell to ring against.
Not too many negatives with this prop, I have had mine several years now with no complaints. The prop will withstand examination if need be. As mentioned before the prop is small so it might now work for standard magic shows. At seances it is a natural and it really has no reset time (but it does have a setup time of about a minute, you cannot have this item sitting on a shelf ready to go, it has to be setup prior to the show but the setup is easy and something most people do quite often in their day to day lives). The bell is not very loud as mentioned above.